In the new study, another gene variant also stood out as an important indicator of butterfly flight ability. New-population females were more often missing a small part of the succinate dehydrogenase gene (Sdhd) and this small deletion was associated with the ability to maintain flight for a greater duration. “The Pgi gene variant seems to be associated with sprinting, and the Sdhd gene variant appears to be associated with endurance,” Marden said. “It’s easy to see why these traits and their associated genes would be found at higher frequencies in new populations. Better flight ability allows certain butterflies to be able to reach and settle new habitat patches.”

Wheat, the paper’s lead author, said, “We already knew about Pgi from previous work in other butterflies and what has been done so far in the Glanville fritillary butterfly. Now with Sdhd we have two genes in the same carbohydrate-metabolism pathway containing alleles of major effect for ecologically important traits.” Marden also commented on the differences in gene expression involving protein dynamics. “Butterflies obtain protein only during larval feeding, whereas the adults rely on nectar, from which they obtain only carbohydrate,” he said. “The timing and level of expenditure of stored proteins is one way to manipulate life history in a species where no more protein will be available to the adult.”

The paper is being published in Molecular Ecology, if someone has access and can send me a copy I would appreciate it. The paper can be found here:

PNAS has a couple of interesting articles in the most recent edition. The first, The evolution of imperfect floral mimicry touches on a subject that fascinated Darwin. I don’t have access to the paper, but here is the abstract:

The question has come up on ScienceBlogs as to which class of invertebrates are the best, coolest, etc. Like PZ I had though about saying Cephalopods (because of those nice octopi that helped the archaeology community find some pottery), but in the end I had to go with Arthropods. Let me give you a few examples as to why.

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"You may not be willing to admit that you resemble an ape; if your thousandth ancestor is more like an ape than you are, you may, if you wish, call it a coincidence. But if that thousandth ancestor's forebears become progressively more simian as you trace back the geneological lines, you will have to admit that somewhere in your family tree there squats an ape." Earnest Hooten

Charles Darwin

"But I had gradually come, by this time, to see that the Old Testament from its manifestly false history of the world, with the Tower of Babel, the rainbow at sign, etc., etc., and from its attributing to God the feelings of a revengeful tyrant, was no more to be trusted than the sacred books of the Hindoos, or the beliefs of any barbarian." Charles Darwin: The Autobiography